device property: attach 'else if' to the proper 'if'

Obviously in the current place the 'else' keyword is redundant, though it seems
quite correct when we check if nval is in allowed range.

Reattach the condition branch there.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>